The best robot lawn mower for your smart garden

Buyers guide: We review the latest smart mowers for your grass

Mowing the lawn can be therapeutic. At least every once in a while it can. However, in spring and summer - when you can almost see the grass growing if you look hard enough - mowing that lawn every few days can become a royal pain in the backside.

That's where a robot lawn mower comes in. Much like the robot vacuum cleaners that they borrow some of their tech and design elements from, robot lawnmowers can make your life a whole lot easier by cutting down on a the effort required to complete a chore.

Much like robot vacuums, though, this new breed of mower is expensive, a bit clumsy and not designed to completely eliminate a task. You can't just chuck one in an overgrown garden and expect miracles. And neither can you expect to never have to get a manual mower out again - or, at least, a strimmer.

Robot lawn mowers are great and we'd definitely say that they are a sound investment - but make sure you know everything you're going to get, and everything you're going to have to prepare, beforehand.

Robot lawn mowers: Considerations before buying

The first thing you need to consider is the shape and size of your garden. If you've got a little square, flat, patch then you'd be mad to splash more than $1,000 on one. Likewise, don't be thrifty if you've got a large, complex lawn, with gradients, ponds, flower beds and other complications for your robot to overcome. You're probably going to need to spend north of $2,000 if you're in that boat - but hey, you live in a house with a great big garden, so you've obviously got loads of cash.

Whatever model you go for, you'll need to be able to power it. Most - if not all - robot mowers come with a base station that plugs in - so you're going to need some outside power. That base station is effectively the lawn mower's home - it's where it goes to charge itself - and so it needs to be easily accessible. Therefore, it will also likely be on-show a little bit. Robot lawn mowers are quite chunky beasts, so think about having one permanently displayed may affect your garden's aesthetics.

You'll need a short lawn to start with, so get your old mower out the shed before you set up your robot. The idea of a robot lawn mower is that it keeps grass short by cutting regularly - as in pretty much non-stop. They only really take breaks to charge (some take a couple of hours, some take nearly all day). Therefore, they don't need a grass box, the short grass trimmings are simply mulched (technical term, Google it) back into the lawn. And that's healthy - a natural feed for your lawn, so win-win.

Now, don't be worrying that it'll get annoying having a lawn mower going for hours every day. And don't worry that it's going to chop your toes off either. They operate really quietly and the blades are tiny. The manufacturers all obviously recommend not letting kids and pets run around while they are operating but, honestly, the worst that would happen is it would bump into you at about 2mph. You'd survive.

Talking of bumping, robot lawnmowers, like their vacuum brethren, will bump off of furniture and the like, so no worries if you have chairs, play sets and the like on your lawn. However, you probably will have to dig a little trench around your garden to bury a boundary guide line - essentially a wire with a small current that connects to the charging station.

This tells your robot mower where not to go - eg flower beds, in ponds, onto patios and so on. If your garden has two areas of grass (i.e. a secondary area) things get a bit more complex with the boundary wire - but it's still possible to do.

As we said up top - don't expect miracles. You can set the distance you want the mower to go past the boundary wire (default is usually around 20cm) but you won't get perfect edges on flower beds, or a close cut around furniture. You will need to do plenty of strimming.

A robot lawn mower will essentially do about 90% of the job of cutting your grass for you - that last 10% you'll have to tidy up yourself.

Robot lawn mowers: Tried and tested

Testing robot lawn mowers takes a long time. It's not just a case of letting one have a quick whizz around your yard and delivering a verdict. They work differently depending on the weather, the season and the amount of time you afford them to be on.

As such, compiling a list of the best robot lawn mowers is an arduous affair but, don't worry - we are on it. Over the last year we've lived with two top models and you can read our verdicts on these below.

Under those, we've also highlighted some other highly rated robot mowers that you may want to consider. We're in the midst of testing more mowers, so be sure to check back soon for any more verdicts we may have delivered.

Husqvarna Automower 450x

The daddy of the robot lawn mower game doesn't come cheap but, if you've got a big, hilly garden then there's no real rival to the 450x. It can handle areas of up to 5,000mÂ² - that's well over an acre in old money - and is the robot mower most capable of navigating big inclines with official support of gradients up to 23 degrees.

It's an absolute beast. It looks like a car - it even has headlights. And the speed in which it moves adds to to the comparison. It flew around our little garden without breaking a sweat - this bad boy was huge overkill in our garden of less than 500mÂ². It can run for well over four hours from a 60 minute charge and it only took around three days to transform our lawn. Everything just looked much neater and healthier.

A cool feature is the spiral spot mode, where the 450x will cut in a spiral pattern away from a central point - do this a few times and it's possible to get a nice pattern on your lawn. However, on the regular cutting mode you don't need to worry about lines or streaks - it actually uses its own built-in GPS to navigate to five different remote start points to randomise the cutting patterns.

That GPS doesn't mean you don't need a boundary wire though - which is a shame. Given the companion app provides a satellite image of where the 450x is, and it uses GPS to navigate, you'd have thought a virtual area could have been set in the app - but not so.

However, that GPS does come in handy when navigating narrow passages. We've got a thin corridor between a kid's jungle gym in our garden and, once the 450x had realised that, it really took its time getting through that, making sure it trimmed all the available grass.

The 450x is clever - and not just the app (which it connects to using its own 3G SIM) - it knows what the weather has been like, so knows whether more or less cutting is required; and it also knows if it's raining - it goes home to its base, if that's the case. It will also sound an alarm if someone takes it away from its cutting zone.

The 450x is absolutely awesome and, despite its bulky size, operates really discretely and does a brilliant job of navigating large, complex gardens. It's like fishing with dynamite if you've only got a small patch of grass, though. The app is great and there are also nice little extras like Apple Watch controls, too. Alexa controls are launching later in 2018.

Gardena Smart Sileno City

Only capable of covering an area a tenth of the size of the 450x - and hills half as steep - the clue is in the name for Gardena's entry level model... it's designed for small urban gardens with a small lawn to manage.

But, even though it's half the size of the much more expensive Husqvarna (same parent company, incidentally) and the cutting width is 50% smaller at 16cm - it has been doing a great job of keeping our lawn in check so far this year - although it did take around a week to get it in order in the first place.

It's a nifty three-wheeler that navigates around garden obstacles well - albeit looking a little clumsy at times and, while the run time is only just over an hour (from an hour's charge), the small area of grass it's charged with maintaining only needs a couple of runs per day.

There's no GPS and you will have to put an extra 'return' boundary wire in your garden to get it back home to its base, but it does retain some security smarts - as you'll need to enter a pin number if it's manually lifted.

At 58db, it hardly makes a sound and the Gardena smart gateway and app also ties in products such as water controls, so you can get your garden fully automated. From within the app you can set schedules for cutting, or you can just leave it to the Smart gateway to keep it going for you.

This Smart Sileno City is a great robot mower for people who just cannot be arsed to get out there every week and maintain their little lawns. It's fairly no frills - but then do you really need frills from a device designed to cut your grass? It takes a little while to get your garden in good shape but, once it does, it maintains it well.

Top robot lawn mowers: Others to consider

As mentioned, we're in the process of fully testing a whole load of other robot mowers, including some of the models listed below...

Robomow RS635 Pro SX

A rival to the 450x at a similar $3,000-ish price point, the RS635 Pro SX employs a dual triangular blade setup to cut grass - combined with a TurboMowâ mode where it will automatically adjust for longer grass, automatically reducing the drive speed while increasing power to the blades. It can cover the same area as the 450x but not handle hills quite so steep.

Flymo 1200R

One of the biggest bargains in the robot lawn mower world, you'll find Flymo's entry level bot on sale for around $600. Your dad had a Flymo lawnmower, didn't he? It's a brand you know has pedigree when it comes to cutting lawns.

Bosch Indego 400 Connect

A mid-ranger that employs parallel blades to cut grass simultaneously, so as it doesn't miss patches. Bosch has also programmed the 400 Connect to begin mowing at different start points every time, in order to reduce over-mowing and streaks. You'll find it for around the $1,000 mark.

Worx WG794 Landroid

For about the same price as Bosch's bot comes the (cleverly named - or at least we think so) Landroid. This robo mower is nice and versatile, built to navigate narrow passages, tackle grass of varying lengths and thickness, and power over inclines of up to 20%. Should it start to rain - or the battery start to run low - the Landroid will scuttle on back to its charging dock.